1. Field of the Invention
This invention relates to an immunologically useful dry-type analytical element for immunoassay according to enzyme immunoassay utilizing antigen-antibody reaction.
2. Description of the Prior Art
Various methods are known for determining biochemical substances contained in a body fluid or the like, and among them, enzyme immunoassay is known as a method capable of measuring them in a relatively high sensitivity. Or the other hand, the method of using a dry-type analytical element has also been developed in view of simplicity and rapidity (U.S. Pat. No. 4,292,272, Japanese Patent KOKAI Nos. 53888/1974, 102388/1984, etc.). It has been desired to develop the dry-type analytical element for immunoassay eliminating both disadvantages of dry-type analytical element method and enzyme immunoassay by combining them. Thereupon, the inventors tried to incorporate the enzyme immunoassay using a water-insoluble macromolecular substrate as the substrate for an enzyme-antibody conjugate described in Japanese Patent KOKAI Nos. 80049/1986 and 80050/1986 into dry-type analytical element. However, troubles often occurred in incorporating the water-insoluble macromolecular substrate into dry-type analytical element, and consequently, the results were not satisfactory. The inventors further investigated, and found that, the aforementioned problems has been remarkably improved by using a water-soluble macromolecular substrate as the substrate of the enzyme-antibody conjugate.